Cold Bore Shots

[Enron Exec]

Ive noticed on many of my rifles that the first round fired is usually off its mark. Why is that and how can one avoid this? For example, i have a bolt action rifle Sig SHR 970 chambered in 300 WM zeroed for 100 yards. The cold bore shot i think landed low left, maybe 2". The 2nd shot would land low left, but halfway to the bulleyes. The rest of the shots end up making a sub 1.5" group when i do my part. I also see this problem with my cold bore shots on a Ruger 10/22 using a match barrel and match grade ammo. The first and 2nd shots might be off by an inch or two, then the groups tighten up.

All this is assuming i did not clean my barrel between the last range trip. I know that cleaning the barrel each time will cause the first few rounds to be off their marks as well.

Thanks for any insight into this.

 

[MT GUNNY]

Float the Barrel.

 

[MrCleanOK]

Materials expand as they heat up. A cold barrel is smaller than a hot one, and will send bullets to a different place. If you use the gun for hunting, where the first shot is usually the only one, then zero it for a dirty cold bore shot. If you use it for target shooting or anything else that will leave you with a hot barrel, zero it for a hot barrel, and just remember where your gun sends bullets when the barrel is cold so you can compensate if need be.

 

[W.E.G.]

Just keep paying attention to what are the rifle's cold-bore tendencies.

Then compensate by your point of aim on any shot where that small difference might matter.
In practice, the issue won't come up much in the field.

 

[Enron Exec]

Nice. Simple solution to a simple problem. TY

 

[rangerruck]

check this thread, and particularly my answer;
http://www.thehighroad.org/showthread.php?t=421607

 

[BigHooter]

anyone ever think about warming up thier bullets to room temp before really wondering why first second and third shots out of a cold bore change POA?
This might be my ignorance but when it comes to hunting rifles, your cold bore shot is usually the only shot you get. Granted sighting in on the range is one thing, but that cold bore shot is what you have to depend on in a hunting situation.
Now back to my warming the bullets up prior to shooting.. it has been said to me, that warming loads up to somewhere to room temp is the only thing you have any control over.. and I am not one to say "nay" to that after punching one 5 round hole @ 100yd with my fathers bench rifle, 6.5 x 47, in 38F temps... the bullet temperature was the only factor I had control over.. and that was achieved by keeping the rounds in my inner vest pocket prior to loading and shooting.
The theory goes that the bullets are loaded around 68-72F and will perform as such at the same temp..
Any opinions? comments? critics?

as I said.. I wasnt going to say boo to a situation that handed me a sub .2" group

 

[lipadj46]

It's not the bullet that matters as it is the barrel that gets hot and deforms.